I have a pierce aero crazy thing and im planning on putting a mvvs .21 or norvel .15 on it but i cant STAND the fork type engine mounts. Is there anyone that knows where i can get a backplate motor mount for one of these type of engines? or a differnt type of .15 thru .25 engine that has one available?

Where in VA are you? You planning on flying combat, or just for fun?

I've not seen backplate mounts done. Probibly because of the expense, and lack of a demand. Most combat planes have a much stronger engine mount than a plastic beam mount anyway.

A backplate mount also means that when it breaks, it's going to be expensive to replace. Or, to keep it from breaking, it will need to be heavy.

If you're not flying combat with it, then it doesn't matter, obviously.

Prob both. All i need is a peice of aluminum with 4 holes in it with the back side counter sunk to accept the engine back plate bolts. Would be prety easy to build i think but then again i dont have the machine shop to do it.

I have done it. I have took an aluminium plate (1mm). You don't need to engrave the plate for screw heads. Just underlay the screws connecting the aluminium plate and firewall to reach the proper distance between both of plates. I have used elastic (rubber) elements for reducing vibration stress to airplane structure.

Milos

Btw, most of the competitive open class designs don't actually have firewalls. Instead, the engine is bolted directly to some kind of frame or crutch or other part. So you don't have a convenient flat chunk of plywood to screw to anyway.

Many scale combat planes are built the same way, though some do have firewalls.